The mouse has become a necessity when using most modern computer programs. Software using windows has been developed in recent years and has become very user-friendly. The computer is given instructions by pointing and clicking with the mouse. However, certain drawbacks have resulted. Unfavourable strain is caused on the arm, shoulder and neck when using the mouse, and gives rise to "mouse arm"0 which is currently a big problem.
Some 40-50 million personal computers are sold annually, for instance. Windows is often installed as standard equipment and a mouse is included in the delivery. "Mouse disease" or RSI (Repetitive Stress Injury) costs the United States approximately seven billion dollars a year in treatment and lost production.
Efforts have been made to solve these problems in various ways, such as by providing support for the hand and/or arm, by means of a foot operated mouse, a trackball or by means of software that forces the user to take a break. However, these methods offer only a slightly reduced risk of injury and therefore do not solve the problem. The injurious static load remains.